Research on fiber-optic etching method for evanescent wave sensors

In order to make high sensitive optical fiber evanescent wave sensors, it is necessary to accurately control the etching process of optical fiber. Traditional methods used time as a parameter to control fiber etching process, corresponding to different fiber diameter. It was easy to be influenced by surrounding temperature and corrosive reagent density. In this paper, fiber spectrometer is used to monitor fiber etching process. Fiber diameter corresponding different absorbance is obtained at different temperature and corrosive reagent density and these results are almost accordant. According to this conclusion, a simple solution to monitor fiber etching process based on single waveband laser response is proposed. Through utilizing this method accurate control of the optical fiber etching process is realized.